Version 1.6.2 released

Security

If a client connects using MQTT v5, will a Will message that has MQTT v5
properties attached, and the very first Will property is one of content-type,
correlation-data, payload-format-indicator, or response-topic, then at
the point the client disconnects, the broker will attempt to read from freed
memory, resulting in a possible crash.

Broker

Fix memory access after free, leading to possible crash, when v5 client with
Will message disconnects, where the Will message has as its first property
one of content-type, correlation-data, payload-format-indicator, or
response-topic. Closes #1244.